Bruce Momjian wrote: > Bruce Momjian wrote: > > > Also, I am wondering whether the information that which index is used to > > > fetch a tuple is always available. I haven't checked, but do we have that > > > information in lossy bitmap heapscan ? > > > > Oh, that is an interesting problem because an index might have one index > > entry representing an entire HOT chain, while another index might > > represent each chain member by individual index entries. When we do the > > bitmaps, don't we access them by heap tid, meaning we would find all > > entries anyway? > > I thinking some more, it would be a problem because while we are merging > the tids, we are using index entries and haven't looked at the heap yet. > I am guessing we would have to exclude the new index from bitmap joins > with other indexes until the VACUUM happens.
Thinking some more, bitmap scans have a mode that tracks just the page numbers, rather than the tids --- if the index visibilities do not match, we would need to fall back to that mode. -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
